1. Field of the General Inventive Concept
Embodiments of the present general inventive concept relate to a developing unit to reduce image faults.
2. Description of the Related Art
Generally, image forming apparatuses are devised to form an image on a printing medium according to inputted image signals. Examples of image forming apparatuses include printers, copiers, facsimiles, and so-called multi-functional devices that combine some of the functionalities of the aforementioned devices.
An image forming apparatus includes a developing unit in which developer is supplied to a photosensitive drum on which an electrostatic latent image has been formed, developing the electrostatic latent image into a visible image.
The developing unit is divided into a developer supply part in which developer is stored and a developing part in which an electrostatic latent image is developed into a visible image using the developer supplied from the developer supply part.
The developer supply part and the developing part of the developing unit may be integrated with each other, or may be separately prepared and detachably coupled to each other.
The developing unit conventionally takes the form of a cartridge, so that main constituent elements required to develop an image, such as a photosensitive drum, charging roller, cleaning roller, developing roller, supply roller, etc., are arranged within a body in the form of a single process cartridge.
In the case of the cartridge-shaped developing unit, nips are conventionally defined between the photosensitive drum and the charging roller and between the charging roller and the cleaning roller during a storage term prior to mounting the developing unit in the image forming apparatus.
More specifically, since the charging roller is compressed by a pressure member to come into press contact with the photosensitive drum, a nip having a predetermined depth is indented in a surface of the charging roller.